Network transmission of video services, such as cable television, video on demand (VOD), and video file downloads continue to proliferate as the network infrastructure continues to evolve to support the high bandwidth demands of applications providing these services. Such a network infrastructure includes headends for providing video services, service nodes for executing applications for delivering the video services, and set-top boxes or other client video device for rendering the service to users. Many video service providers (VSPs) that use hybrid fiber coax (HFC) networks have video on demand (VOD) systems deployed. These systems allow the subscriber to navigate a menu system or search for content to watch, purchase or play the content, and view it on their television using a QAM device (e.g. settop box with two-way RF communications) to receive the content from the network.
Unlike conventional IP networks such as the Internet, a network infrastructure for delivering media services is typically arranged in a fanning out manner from the head end, since the bulk of the message traffic travels from the headend (service provider) to the settop boxes in a so-called downstream direction. Upstream signals, typically control information such as VOD and channel selection requests, travel upstream toward the headend. In contrast to the typical IP network, arranged for roughly equal volumes of bi-directional traffic, the media services network infrastructure accommodates larger volumes of downstream traffic, and generally transports data only between the headend and the settop boxes, not between individual settops.
While generally available programming (i.e. basic cable) is typically available to all set top boxes, in a so-called “broadcast” transmission, other services such as video-on-demand are sent to individual set-top boxes on “narrowcast” channels. In a conventional video services network, each of the set-top boxes receives particular channels, or frequency ranges, for narrowcast video services, generally based on the physical arrangement of the delivery infrastructure connections that branch to different service groups. These frequency ranges, or channels, are thus “visible” to the set top box, and are common to all set-top boxes in the service group. The headend maintains a mapping of set-top boxes to service groups, and further maps each service group to the channels, or frequency ranges, applicable to the group. Thus, when a user requests a service, the headend identifies the set-top box making the request, and identifies the service group and channels assigned to that group for transmitting the service.